Golf club head and method of fabricating striking plate

ABSTRACT

A golf club head including a head body and a striking plate is provided. The head body has an opening. The striking plate is disposed at the opening and has a striking surface. The striking plate includes a first crystallization phase region and at least a second crystallization phase region. The second crystallization phase region is located in the first crystallization phase region. The second crystallization phase region extends from the striking surface to an interior of the striking plate. The elastic modulus of the second crystallization phase region is smaller than that of the first crystallization phase region.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan applicationserial no. 95139354, filed Oct. 25, 2006. All disclosure of the Taiwanapplication is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a golf club head and a method offabricating a striking plate, and more particularly to a golf club headwith a striking plate having a crystallization phase region with a lowelastic modulus and a method of fabricating the striking plate.

2. Description of Related Art

With the prevailing of sports in today's society, golf has become one ofthe favorite sports widely accepted by the mass, and more and morepeople are participating in the golf sports. Golf clubs can beclassified into wooden clubs, iron clubs, putters, and so on accordingto various fields and usage.

As for the wooden club, the golf club head is usually fabricated byfirst forming a head body made of a metal material or together withcarbon fiber, and then, integrating a striking plate for striking a golfball with the head body as a whole. The golf club head has a specificspecification and limitation in size and weight, so as to provide adesired controlling and striking effect when striking the golf ball.Therefore, depending upon different requirements in use, in the designof the golf club head, the basic architecture of the head body and thestriking plate or the combination constitution thereof is generallychanged to achieve the optimal design.

The region with a high coefficient of restitution (COR) of thehomogeneous and uniform striking plate is usually located in the centerregion, and the COR of the striking plate is gradually reduced as beingfar away from the center region. As far as the COR of the striking plateis concerned, the larger the region with a high COR of the strikingplate of the golf club head is, the better the striking effect of thestriking plate is. Therefore, in the conventional design of strikingplate of the golf club head, the thickness of the plate is reduced toincrease the striking restitution capability, but meanwhile thedurability of the striking plate is degraded. The striking plate may beeasily damaged after a long time of striking as the thickness isreduced. How to simply and effectively increase the striking restitutioncapability of the striking plate without degrading the durability hasbecome an urgent problem to be solved in the design of the golf clubhead.

SUMMARY OF THE INVENTION

The present invention is directed to a gold club head, wherein thestriking plate has a larger region with a high COR.

The present invention is also directed to a method of fabricating thestriking plate, so as to enlarge the region of the striking plate with ahigh COR.

The present invention provides a golf club head, which comprises a headbody and a striking plate. The head body has an opening. The strikingplate is disposed at the opening and has a striking surface. Thestriking plate comprises a first crystallization phase region and atleast a second crystallization phase region. The second crystallizationphase region is located in the first crystallization phase region andextends from the striking surface to an interior of the striking plate.The elastic modulus of the second crystallization phase region issmaller than that of the first crystallization phase region.

In an embodiment of the present invention, a crystallization phase ofthe first crystallization phase region includes β-type or α-β-type.

In an embodiment of the present invention, a crystallization phase ofthe second crystallization phase region includes α′-type or α″-type.

In an embodiment of the present invention, the elastic modulus of thefirst crystallization phase region may be larger than or equal to 100GPa.

In an embodiment of the present invention, an absolute value of thedifference between the elastic modulus of the first crystallizationphase region and that of the second crystallization phase region may belarger than or equal to 5 GPa and smaller than or equal to 10 GPa.

In an embodiment of the present invention, the striking plate is made ofa Ti alloy.

The present invention provides a method of fabricating the strikingplate, which is applicable for a golf club head. The method offabricating the striking plate comprises the following steps. First, aplate body is provided, and a crystallization phase of the plate body isa first crystallization phase. Next, a part of the plate body is heated.Next, the heated part of the plate body is quenched, so as to make thecrystallization phase of the part of the plate body be transformed intoa second crystallization phase.

In an embodiment of the present invention, the step of heating the partof the plate body may be achieved by irradiating the plate body with ahigh-energy laser beam.

In an embodiment of the present invention, the step of heating the partof the plate body may be achieved by irradiating the plate body with anelectron beam.

In an embodiment of the present invention, the step of quenching theheated part of the plate body may be achieved by water cooling, aircooling, or furnace cooling.

In an embodiment of the present invention, a cooling rate of quenchingthe heated part of the plate body is higher than or equal to 10° C. persecond.

In an embodiment of the present invention, the first crystallizationphase includes β-type or α-β-type.

In an embodiment of the present invention, the second crystallizationphase includes α′-type or α″-type.

In an embodiment of the present invention, the plate body is made of aTi alloy.

Based on the above, since the striking plate of the present inventionhas the second crystallization phase region with a lower elasticmodulus, on the whole, the striking plate of the present invention has alarger region with a high COR. In addition, in the method of fabricatingthe striking plate of the present invention, the second crystallizationphase region with low elastic modulus is formed in the plate body bypartially heating and quenching, without degrading the durability of thestriking plate, so the region of the striking plate with a high COR isenlarged. In addition, in the method of fabricating the striking plateof the present invention, the method of irradiating with the laser beamor the electron beam may be adopted to partially heat the plate body, sothe method of fabricating the striking plate of the present invention issimple and the manufacturing cost is low.

In order to make aforementioned features and advantages of the presentinvention comprehensible, a preferred embodiment accompanied withfigures is described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic exploded view of a golf club head according to anembodiment of the present invention.

FIG. 2 is a schematic side view of the striking plate of FIG. 1.

FIGS. 3A to 3C are schematic process flow views for fabricating thestriking plate of FIG. 1.

DESCRIPTION OF EMBODIMENTS

Referring to FIGS. 1 and 2, FIG. 1 is a schematic exploded view of agolf club head according to an embodiment of the present invention, andFIG. 2 is a schematic side view of the striking plate of FIG. 1. Thegolf club head 200 of this embodiment includes a head body 210 and astriking plate 220. The head body 210 has an opening 212. In thisembodiment, the head body 210 may be a shell, and integrally formed by acommon metal material (e.g., stainless steel) by way of lost-wax casing.

Alternatively, in other embodiments of the present invention, the headbody 210 may be made of composite material of metal and high molecularplasticizing material or high strength fiber material (e.g., carbonfiber), and it is fabricated by the following steps. A crown (not shown)is separately prefabricated by injection molding or thermal compressionmolding, and then, the crown is embedded into another part of the metalshell. Alternatively, a carbon fiber pre-preg may be directly adhered onthe hollow portion of the metal shell, and then heated by the use of amold and an air bag so as to forming the body 210.

The striking plate 220 is disposed at the opening 221, for composing thegolf club head 200 together with the head body 210. The striking plate220 has a striking surface 222, and the striking plate 220 includes afirst crystallization phase region 224 and at least one secondcrystallization phase region 226 (two second crystallization phaseregions are schematically shown in FIG. 1). The second crystallizationphase regions 226 are located in the first crystallization phase region224, and extend from the striking surface 222 to an interior of thestriking plate 220, and the elastic modulus of each secondcrystallization phase region 226 is smaller than that of the firstcrystallization phase region 224. In this embodiment, the secondcrystallization phase regions 226 are usually located outside of thecenter region 228 of the striking plate 220.

In this embodiment, a crystallization phase of the first crystallizationphase region 224 includes β-type or α-β-type. The so-called β-typecrystallization phase indicates that the crystallization mode isbody-centered cubic lattice (BCC lattice), and the so-called α-β-typecrystallization phase indicates that the crystallization modes includehexagonal close-packed lattice (HCP lattice) and BCC lattice. Moreover,a crystallization phase of each second crystallization phase region 226includes α′-type or α″-type. The so-called α′-type crystallization phaseindicates a hexagonal martensite, the so-called α″-type crystallizationphase indicates an orthorhombic martensite, and both of them areincomplete-transformation crystallization phases formed due to quickcooling. Under the incomplete-transformation phase, the Ti alloy has alow elastic modulus.

It should be noted that, the so-called elastic modulus is Young'smodulus, with the metric unit as Pascal (Pa for short). The elasticmodulus of the material (usually a single atom metal or alloy) isinversely proportional to the COR, that is, the lower the elasticmodulus of the material is, the higher the COR is. Therefore, not onlythe center region 228 of the striking plate 220 of this embodiment has arelatively high COR, but the second crystallization phase regions 226 ofthe striking plate 220 also have a relatively high COR, on the whole,the striking plate 220 has a larger region with high COR. In addition,in this embodiment, the elastic modulus of the first crystallizationphase region 224 may be larger than or equal to 100 GPa (i.e., 100*10⁹Pa), and a absolute value of the difference between the elastic modulusof the first crystallization phase region 224 and that of the secondcrystallization phase region 226 may be larger than or equal to 5 GPaand smaller than or equal to 10 GPa.

It should be noted that, in this embodiment, the striking plate 220 maybe made of Ti alloy, for example, Ti-6Al-4V alloy, that is, the Ti alloywith the components of 90 wt % Ti, 6 wt % Al, and 4 wt % V. However, inanother embodiment, the striking plate 220 is made of other kinds of Tialloys, for example, Ti-8Al-1Mo-1V, Ti-6Al-2Sn-4Zr-2Mo, Ti-6Al-6V-2Sn,Ti-6Al-2Sn-4Zr-6Mo, Ti-8Mn, Ti-10V-2Fe-3Al, Ti-11.5Mo-6Zr-4.5Sn,Ti-15Mo-5Zr-3Al, and Ti-13V-11Cr-3Al.

Referring to FIG. 1, it should be noted in this embodiment that, thehead body 210 and the striking plate 220 may be bonded through embeddingand/or soldering. Furthermore, before the striking plate 220 ispositioned, the solder may be pre-coated on the bonding surface of thehead body 210 and the striking plate 220. Then, the striking plate 220is disposed at the opening 212 of the head body 210, and then solderedsuch that the solder is melted and cooled so as to form a solderinglayer (not shown) for connecting the head body 210 with the strikingplate 220. Moreover, in another embodiment, first, the striking plate220 is disposed at the opening 212 of the head body 210, and then, thesolder is coated on the seam at the bonding position of the head body210 and the striking plate 220, and after the solder is melted into thebonding surface, the soldering layer (not shown) is formed by coolingand solidification.

After the fabrication of the head body 210 of the gold club head 200,and the assembling of the head body 210 with the striking plate 220 iscarried out. The method of fabricating the striking plate 220 isdescribed below in detail. FIGS. 3A to 3C are schematic process flowviews for fabricating the striking plate of FIG. 1. The method offabricating the striking plate 220 of this embodiment includes thefollowing steps. First, referring to FIG. 3A, a plate body P isprovided, and a crystallization phase of the plate body P is a firstcrystallization phase. In this embodiment, the first crystallizationphase includes β-type or α-β-type.

Next, referring to FIG. 3B, the plate body P is partially heated, thatis, a part of the plate body is heated. In this embodiment, the step ofpartially heating the plate body P may be achieved by irradiating theplate body P with a high-energy laser beam L. In another embodiment, thestep of partially heating the plate body P may be achieved byirradiating the plate body P with an electron beam (not shown).

Next, referring to FIG. 3C, the heated part of the plate body P isquenched such that the crystallization phase of the part of the platebody P is transformed into a second crystallization phase to form atleast a second crystallization phase region 226 (two secondcrystallization phase regions are shown in FIG. 3C). Moreover; the stepof quenching the heated part of the plate body P may be achieved bywater cooling, air cooling, or furnace cooling, and a cooling rate forquenching the heated part of the plate body P may be larger than orequal to 10° C. per second. Furthermore, the second crystallizationphase includes α′-type or α″-type.

After the steps of FIGS. 3A to 3C, a striking plate 220 with a firstcrystallization phase region 224 (with the first crystallization phase)and a plurality of second crystallization phase regions 226 (with thesecond crystallization phase) are substantially completed. In anotherembodiment, the appearance or the striking surface 222 of the strikingplate 220 may be further processed, so as to make the appearance of thestriking plate 220 correspond to the appearance of the opening 212 ofthe head body 210 (shown in FIG. 1), thus, the striking surface 222achieves the required surface roughness.

To sum up, the golf club head and the method of fabricating the strikingplate of the present invention at least have the following advantages.

First, since the striking plate of the present invention has the secondcrystallization phase region with a relatively low elastic modulus, thatis, the second crystallization phase region is a relatively high COR, onthe whole, the striking plate of the present invention has a largerregion with a high COR.

Second, since in the method of fabricating the striking plate of thepresent invention, the second crystallization phase region with a lowelastic modulus is formed in the plate body by partially heating andthen quenching, without degrading the durability of the striking plate,the region with a high COR of the striking plate is enlarged.

Third, since in the method of fabricating the striking plate of thepresent invention, the method of irradiating with the laser beam or theelectron beam are adopted to partially heat the plate body, the methodof fabricating the striking plate of the present invention is simple andthe manufacturing cost is low.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

1. A golf club head, comprising: a head body, having an opening; and a striking plate, disposed at the opening and having a striking surface, wherein the striking plate comprises: a first crystallization phase region; and at least a second crystallization phase region, located in the first crystallization phase region, wherein the second crystallization phase region extends from the striking surface to an interior of the striking plate, and the elastic modulus of the second crystallization phase region is smaller than that of the first crystallization phase region.
 2. The golf club head as claimed in claim 1, wherein a crystallization phase of the first crystallization phase region includes β-type or α-β-type.
 3. The golf club head as claimed in claim 1, wherein a crystallization phase of the second crystallization phase region includes α-type or α″type.
 4. The golf club head as claimed in claim 1, wherein the elastic modulus of the first crystallization phase region is larger than or equal to 100 GPa.
 5. The golf club head as claimed in claim 1, wherein an absolute value of the difference between the elastic modulus of the first crystallization phase region and the second crystallization phase region is larger than or equal to 5 GPa and smaller than or equal to 10 GPa.
 6. The golf club head as claimed in claim 1, wherein the striking plate is made of Ti alloy.
 7. A method of fabricating the striking plate, applicable for a golf club head, comprising: providing a plate body, wherein a crystallization phase of the plate body is a first crystallization phase; heating a part of the plate body; and quenching the heated part of the plate body to transform the crystallization phase of the part of the plate body into a second crystallization phase.
 8. The method of fabricating the striking plate as claimed in claim 7, wherein the step of heating the part of the plate body is achieved by irradiating the plate body with a high-energy laser beam.
 9. The method of fabricating the striking plate as claimed in claim 7, wherein the step of heating the part of the plate body is achieved by irradiating the plate body with an electron beam.
 10. The method of fabricating the striking plate as claimed in claim 7, wherein the step of quenching the heated part of the plate body is achieved by water cooling, air cooling, or furnace cooling.
 11. The method of fabricating the striking plate as claimed in claim 7, wherein a cooling rate of quenching the heated part of the plate body is larger than or equal to 10° C. per second.
 12. The method of fabricating the striking plate as claimed in claim 7, wherein the first crystallization phase comprises β-type or α-β-type.
 13. The method of fabricating the striking plate as claimed in claim 7, wherein the second crystallization phase comprises α′-type or α″-type.
 14. The method of fabricating the striking plate as claimed in claim 7, wherein the plate body is made of Ti alloy. 